1. Technical Field
This invention relates generally to asymmetric digital subscriber line network management systems. More particularly, the invention relates to a system and method for operating a digital subscriber line access multiplexer for an asymmetric digital subscriber line network.
2. Description of Related Art
An Asymmetric Digital Subscriber Line (ADSL) is a modem technology for converting existing copper twisted-pair telephone lines into access paths for delivering broadband services such as multimedia and high-speed data communications to homes and small businesses. For home or small business use, subscribers tend to be more of a consumer of data rather than a producer of data. Therefore, slower upstream information speed can be traded off for faster downstream information speed. In other words, in an ADSL subscriber line network much greater bandwidth is available in the downstream direction rather than the upstream direction. An ADSL subscriber line can transmit up to 6 Mbps to a subscriber while it can transmit at 832 kbps or more bi-directionally over existing copper telephone lines. These data rates can expand existing access capacity fifty fold, thus enabling the transformation of existing public information networks without requiring new cabling. With ADSL technology, the existing public information networks, which are generally limited to voice, text and low resolution graphics, can be transformed into a system that is capable of bringing broadband services such as full motion video, to a subscriber's home or small business. See, for example, Twisted Pair Access to the Information Superhighway, at www.telebyteusa.com/dslprimer/dslch3.htm which is herein incorporated by reference in its entirety.
A Digital Subscriber Line Access Multiplexer (DSLAM) switch provides high-speed data transmission over existing copper telephone lines. A DSLAM switch separates the voice frequency signals from the high-speed data traffic, controls and routes traffic in an ADSL subscriber line between the subscriber's end-user equipment such as a router, modem or network interface card, and the network service provider's network. In general, a DSLAM switch aggregates multiple subscriber lines at an input portion into a single output for network connection. See, for example, The Role of the DSLAM, Chapter 3, at telebyteusa.com/dslprimer/dslch3.htm, which is incorporated herein by reference in its entirety.
Current methods for connecting DSLAM switches in an ADSL network do not differentiate between batch provision requests and Graphic User Interface (GUI) operator initiated provision requests. Therefore, a GUI operator may have to wait an unacceptable amount of time (e.g., more than 20 minutes at times when there are a lot of batch provisioning orders) for their provision request to get through the DSLAM switch. Those skilled in the art will appreciate that a provision request is a request for supplying telecommunication services to one or more users, including the act of providing sufficient switching equipment.
DSLAM switches are network elements that are normally controlled by an Element Management System (EMS), such as for example an ALCATEL 5522 AWS Element Manager. One EMS can control up to hundreds of DSLAM switches, for example. A connection request on a DSLAM switch is made through an EMS. Normally only one gateway is provided between a Network Management System (NMS) and an EMS. This conventional architecture is limited to providing only one connection request being processed through an EMS, even though there may be many connection requests on different DSLAM switches at the same time.
Accordingly, there is a need in the art for an EMS to provide multiple gateways for communicating with a NMS and maximizing the utilization of the EMS and corresponding DSLAM switches controlled by the EMS. Conventional methods for managing DSLAM switch connections require that a control algorithm associated with the NMS process each connection request serially. Because each EMS can manage many DSLAM switches, when a connection request is made on the DSLAM switch there is a need to communicate to the same EMS that is trying to build up connections on other DSLAM switches distributed across the ADSL network. For nightly provisions, for example, there may be hundreds or thousands of installed connections going through the EMS to the DSLAM switches. Conventional control algorithms, however, only allow one connection to go through the EMS regardless of which DSLAM switch the connections are made to. For example, if five cross connections have to be made, then all five cross connections have to be queued into the EMS one by one. Accordingly, the NMS must wait until all five cross connections are queued into the EMS and until a first connection reaches its provision, a second connection cannot start trying to reach its provision.
A Permanent Virtual Circuit (PVC) is defined to provide a virtual circuit connection between a user's home and a network service provider. The PVC provides a connection that is equivalent of a dedicated private line service. Whenever a queued connection is sent to the proper DSLAM switch there is only one activity occurring in one of the PVCs established through the EMS. If two cross connection requests are sent concurrently to one DSLAM switch, however, the NMS will not know which response is associated with which connection request whenever the DSLAM switch sends a response back to the NMS. Further, sending two cross connection requests concurrently can actually cause trouble internally. One problem with using the conventional control algorithm is speed. Conventional control algorithms are very slow because only one connection can be made by the EMS through each DSLAM switch at any one time. For example, whenever two or three thousand PVCs are established in one day, the EMS must make an equivalent number of connections through each of the DSLAM switches. Accordingly, if multiple connections can be made through the EMS by a better control algorithm, overall system performance and throughput can be improved.
Another problem with conventional control algorithms is the use of automatic-batch provisioning when there are no users issuing commands and defining the several thousands of PVC provision requests. In other words, whenever, the system operates automatically. If a user, however, wants to issue a command to make a connection from a data center, the user will generally issue a provision request command from a GUI window. When the user issues the GUI command and there is traffic from other previously issued provision requests, then the user's provision request must wait in a queue until the GUI request can be processed. If there are other queued requests, for example, then a request from the user's GUI window will be placed in the back of the queue. The user, therefore, cannot get through until the other requests are processed. Because these other requests can number in the hundreds, the user must wait for an unacceptable amount of time. For example, in some conventional systems, the user can wait up to one half hour and even up to one hour before a GUI request is placed into the queue and is eventually connected to one of the dedicated DSLAM switches.
The problems described above exist with conventional NMS and EMS control algorithms because the NMS and EMS operate under what is generally referred to as semaphore control. Conventional semaphore control is implemental only at one level and it is not efficient because of its serial nature, allowing only one connection request to be processed at any one time. This serial processing creates two problems, for example. First, the throughput problem discussed above and, second, the GUI user problem whereby the GUI user is not given priority when the user's connection or provision request is sent. It may be difficult or impossible to actually surpass all the batch orders that may be queued before the GUI request. Therefore, there is a need for a GUI user's request to bypass all the batch orders and be processed with priority such that the GUI user can obtain a response relatively quickly.
Therefore there is a need for a new control algorithm for controlling a NMS and an EMS in a Digital Subscriber Line (DSL) network to solve the above-referenced problems. For example, there is a need to confirm multiple cross connections that are issued through the EMS to the multiple DSLAM switches. There is also a need to implement a two level semaphore control at the NMS level. For example, there is a need to provide one level of control at the DSLAM switch and another level of control at the EMS. There is also a need in the art for a method of supporting multiple gateways communicating with one EMS and enforced by an Object System Integrator (OSI) on a NMS platform.